Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes

The aim of the research is the development of a one-pot method for the synthesis of lignans, natural compounds that show a wide spectrum of biological activities. For this purpose, the <i>ansa</i>-zirconocenes of various structures were tested as catalysts of allylbenzene cyclometalation...

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Main Authors: Pavel V. Kovyazin, Pavel V. Ivchenko, Ilya E. Nifant’ev, Lyudmila V. Parfenova
Format: Article
Language:English
Published: MDPI AG 2021-11-01
Series:Chemistry Proceedings
Subjects:
Online Access:https://www.mdpi.com/2673-4583/8/1/60
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author Pavel V. Kovyazin
Pavel V. Ivchenko
Ilya E. Nifant’ev
Lyudmila V. Parfenova
author_facet Pavel V. Kovyazin
Pavel V. Ivchenko
Ilya E. Nifant’ev
Lyudmila V. Parfenova
author_sort Pavel V. Kovyazin
collection DOAJ
description The aim of the research is the development of a one-pot method for the synthesis of lignans, natural compounds that show a wide spectrum of biological activities. For this purpose, the <i>ansa</i>-zirconocenes of various structures were tested as catalysts of allylbenzene cyclometalation with ethylaluminum dichloride (EtAlCl<sub>2</sub>) and Mg. The effects of the organophosphorus compounds, hexamethylphosphoramide (HMPA) and triphenylphosphine (PPh<sub>3</sub>), on the chemo- and regioselectivity of the reaction were studied. The use of <i>η</i><sup>5</sup>-indenyl or fluorenyl <i>ansa</i>-complexes with ethanediyl or dimethylsilylene bridges, as well as a biscyclopentadienyl complex with Si-bound ligands as catalysts in the presence of HMPA, yields the formation of cyclometalation products in a total yield of 70%. Cyclometalation product composition is represented by two regioisomers, 3,4-dibenzyl- and 2,4-dibenzyl-substituted alumolanes, with a ratio of (1-2):1, in which hydrolysis provides corresponding dibenzylbutane lignan and 9,8′-neo-lignan.
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spelling doaj.art-efdeb8393fef4fabaf3ebe142cc4f8422023-11-17T10:18:52ZengMDPI AGChemistry Proceedings2673-45832021-11-01816010.3390/ecsoc-25-11776Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-ComplexesPavel V. Kovyazin0Pavel V. Ivchenko1Ilya E. Nifant’ev2Lyudmila V. Parfenova3Institute of Petrochemistry and Catalysis of Russian Academy of Sciences, Prospekt Oktyabrya, 141, 450075 Ufa, RussiaA. V. Topchiev Institute of Petrochemical Synthesis RAS, Leninsky Avenue 29, 119991 Moscow, RussiaA. V. Topchiev Institute of Petrochemical Synthesis RAS, Leninsky Avenue 29, 119991 Moscow, RussiaInstitute of Petrochemistry and Catalysis of Russian Academy of Sciences, Prospekt Oktyabrya, 141, 450075 Ufa, RussiaThe aim of the research is the development of a one-pot method for the synthesis of lignans, natural compounds that show a wide spectrum of biological activities. For this purpose, the <i>ansa</i>-zirconocenes of various structures were tested as catalysts of allylbenzene cyclometalation with ethylaluminum dichloride (EtAlCl<sub>2</sub>) and Mg. The effects of the organophosphorus compounds, hexamethylphosphoramide (HMPA) and triphenylphosphine (PPh<sub>3</sub>), on the chemo- and regioselectivity of the reaction were studied. The use of <i>η</i><sup>5</sup>-indenyl or fluorenyl <i>ansa</i>-complexes with ethanediyl or dimethylsilylene bridges, as well as a biscyclopentadienyl complex with Si-bound ligands as catalysts in the presence of HMPA, yields the formation of cyclometalation products in a total yield of 70%. Cyclometalation product composition is represented by two regioisomers, 3,4-dibenzyl- and 2,4-dibenzyl-substituted alumolanes, with a ratio of (1-2):1, in which hydrolysis provides corresponding dibenzylbutane lignan and 9,8′-neo-lignan.https://www.mdpi.com/2673-4583/8/1/60cyclometalationalkeneszirconoceneslignane
spellingShingle Pavel V. Kovyazin
Pavel V. Ivchenko
Ilya E. Nifant’ev
Lyudmila V. Parfenova
Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes
Chemistry Proceedings
cyclometalation
alkenes
zirconocenes
lignane
title Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes
title_full Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes
title_fullStr Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes
title_full_unstemmed Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes
title_short Synthesis of Dibenzylbutane and 9,8′-Neo-Lignans via Cyclometalation of Allylbenzene by EtAlCl<sub>2</sub> and Mg in the Presence of Zr <i>ansa</i>-Complexes
title_sort synthesis of dibenzylbutane and 9 8 neo lignans via cyclometalation of allylbenzene by etalcl sub 2 sub and mg in the presence of zr i ansa i complexes
topic cyclometalation
alkenes
zirconocenes
lignane
url https://www.mdpi.com/2673-4583/8/1/60
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AT ilyaenifantev synthesisofdibenzylbutaneand98neolignansviacyclometalationofallylbenzenebyetalclsub2subandmginthepresenceofzriansaicomplexes
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